A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This large, circular tomb is the final resting place of the first emperor of Rome.

An 18th century fountain and two columns are all that remains of Rome's forgotten river harbor.

This curious, round temple is the oldest still-standing marble building in Rome.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

The first statue to be added to Saint Peter's Square in over 350 years is an ode to migrants and refugees around the world.

Ancient ruins hidden underneath a modern luxury hotel.

A sculpture serving as an homage to Pope John Paul II.

Its interior is adorned with some of the best examples of early Christian mosaics.

Artworks by loners, prisoners and the criminally insane.

Florentine Renaissance style building in Switzerland, home to the world's largest taxidermy Great White Shark.

A constellation of golden cobblestones shows the names of local children born under a full moon.

Museum of science fiction, utopias, and extraordinary journeys of the mind.

An amazing clockwork museum in the Val de Travers holds examples of various prestigious legacies horological history.

These magnificent 240-year-old machines are considered distant ancestors of the computer.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

Breathtaking and huge 430 year old maps of Italy.

If you want to talk to the Pope you will have to stare down this surreal vision of Jesus rising from a nuclear hell.

These spartan apartments are provided to clergymen visiting Vatican City.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

The Vatican's secret porn-festooned bathroom was painted in erotic murals by one of the greatest artists of the Renaissance.